Caption: Copper heads and mould. Set of heads showing the process of copper casting. Casting is the process of using a mould to shape an object from a molten material. Copper, which is a chemical element, is a metal that melts at 1084 degrees Celsius. The mould (grey, left) is used to create a void in a casting material. Molten copper, melted in a furnace, is then poured into this void. Once the metal has set it has a green patina of copper oxide covering the surface (centre). Polishing removes this oxide to produce a shiny surface (yellow, right). Photographed in the UK. See images T810/256-259 for images showing the pouring of the molten copper into the moulds. T810/259 and T810/260 show close-ups of the furnace and mould.